The show is earning every viewer it catches. For most of its episodes so far, it’s had to grab them while airing against some of the toughest competition on television, HBO’s “Game of Thrones.”

In its first four episodes, “Halt” earned 1.5 million total viewers, 644,000 of them in the key 18-49 demographic, based on live-plus-three averages that measure viewing over three days. (Ratings for Sunday’s fifth episode — one of the show’s best, in your humble correspondent’s opinion — will be available later this week.)

Last week, the first in which it didn’t face “Thrones,” “Halt” climbed to 774,000 total viewers in the key demo, a 42 percent increase from the week before.

The 774,000 viewers topped the seasonal demo average for “Turn,” the new Revolutionary War drama that AMC just renewed. “Turn” averaged 2 million total viewers, 709,000 aged 18-49.

Another comparison: AMC’s “Low Winter Sun,” canceled last year after one season, scored 1.6 million total viewers, 772,000 of them in the key demo. Yes, it outperformed “Halt” so far. But “Low Winter Sun” followed an explosively successful final season of “Breaking Bad,” and lost lots of its lead-in.

In its third and last season on AMC (the show is moving to Netflix), “The Killing” averaged 2.1 million total viewers, 1 million of them in the key demo. But it had “Mad Men” for a lead-out for a few weeks, and one week followed a marathon of “The Walking Dead,” the top-rated scripted show on television.

Also, advertisers like the fact that “Halt” viewers can afford fancy roadsters like the one Joe slammed into an armadillo in the show’s premiere. AMC boasts that “Halt” has the No. 3most upscale audience in the key demo, with 42 percent of viewers coming from households with combined incomes of $100,000 or more. According to Nielsen data, “Mad Men” is No. 1 at 50 percent, and the “The Good Wife” is No. 2.

“Halt” is also doing pretty well with critics. It received 79 percent positive reviews on Rotten Tomatoes, compared to 45 percent from “Low Winter Sun.”

And AMC has another reason not to wait for halt to catch a little more fire: With “Breaking Bad” gone and “Mad Men” ending next year, it needs another show to pull in Emmys. Even if it doesn’t match the killer ratings for “The Walking Dead.”